PHYSIOLOGY
CENTRAL NERVOUS SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Sodium channels close, potassium channels open
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Sodium channels open, potassium channels open,
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Sodium channels open, potassium channels close
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Potassium channels open, sodium channels open
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Detailed explanation-1: -First is depolarization, followed by repolarization and a short period of hyperpolarization. These three events happen over just a few milliseconds.
Detailed explanation-2: -In neurons, the rapid rise in potential, depolarization, is an all-or-nothing event that is initiated by the opening of sodium ion channels within the plasma membrane. The subsequent return to resting potential, repolarization, is mediated by the opening of potassium ion channels.
Detailed explanation-3: -An action potential can be further broken down into its separate stages: depolarization, repolarization, hyperpolarization, and the refractory period.
Detailed explanation-4: -An action potential has three phases: depolarization, overshoot, repolarization. There are two more states of the membrane potential related to the action potential. The first one is hypopolarization which precedes the depolarization, while the second one is hyperpolarization, which follows the repolarization.
Detailed explanation-5: -Phase zero is the phase of depolarization. Phases one and two are not present in pacemaker cells. Phase three is repolarization, involving the closing of Ca2+ channels, blocking the flow of Ca2+ ions. Phase four, a phase of gradual depolarization, is unique to the pacemaker cells. 21-Apr-2022